This photo taken on August 7, 2016 shows mahjong enthusiasts playing mahjong under water in a swimming pool at a diving club in the Chinese city of Chongqing. Only participants with proper diving certification were allowed to take part in the underwater competition. (Photo by AFP Photo/Stringer)

Ukrainians swim in an ice hole as part of the celebration of the Epiphany in Kiev, Ukraine, Monday, January 19, 2015. Orthodox believers celebrate the holiday of the Epiphany on Jan. 19, and traditionally bathe in holes cut through thick ice on rivers and ponds to cleanse themselves with water deemed holy for the day. (Photo by Sergei Chuzavkov/AP Photo)

People dressed as mermaids and mermen take part in the group swim during the MerMagic Convention at the Freedom Aquatic & Fitness Center in Manassas, Virginia on March 4, 2023. The event bills itself as the “World's Largest Mermaid Convention”. (Photo by Joseph Prezioso/AFP Photo)

Trainers from Tianjiao Special Guard/Security Consultant Ltd. Co. engage trainees dressed in swimming suits as they crawl on the beach during a training session in Sanya, Hainan province January 8, 2012. (Photo by CHINA DAILY/Reuters)

This undated handout picture taken by Tim Samuel and provided through his Instagram account shows a small fish swimming inside the belly of a jellyfish off the coast of Byron Bay in New South Wales, eastern Australia. A fish has been pictured swimming inside a jellyfish off Australia's east coast in a remarkable and rare image that has gone viral, with more than two million online views. Underwater photographer Tim Samuel was in the water with a friend near popular tourist resort Byron Bay in December when they came across the little creature trapped inside the only slightly larger jellyfish. (Photo by Tim Samuel Photography/AFP Photo/Instagram)

Stephen McDonagh takes part in the Irish Bog Snorkelling championship at Peatlands Park on July 27, 2014 in Dungannon, Northern Ireland. The annual event sees male and female competitors swim the 60m length of the bog watched by scores of spectators and takes place on International Bog Day. (Photo by Charles McQuillan/Getty Images)

A picture taken on March 16, 2017 shows women dressed up as mermaids posing by a pool at a mermaid training school in Moscow. Russian women who have dreamt of becoming a mermaid since their youngest years, start turning their fantasies into reality with a new type of fitness – mermaid swimming. (Photo by Natalia Kolesnikova/AFP Photo)

This picture taken with an underwater camera shows Japan' s Yumi Adachi competing in the Mixed Duet technical final during the synchronised swimming competition at the 2017 FINA World Championships in Budapest, on July 17, 2017. (Photo by Bernadett Szabo/Reuters)